The 20 inches was closer to 14 but still a deluge ,a storage tot I leave out on the backyard was 2 inches from the top , a 5 gallon bucket completely full gives you an indication of what took place .It started at 11 pm til around 6 am . The U.S. record for rainfall in 24 hrs was recorded in this local ,THE Alvin area recorded 43 inches in one day.